Radio frequency identification tags and radio frequency identification tag systems are known, and find numerous uses. In general, radio frequency identification tags are capable of retaining and, in operation, transmitting a substantial amount of information--sufficient information to uniquely identify individuals, packages, inventory and the like. The radio frequency identification tag is also capable of receiving and storing information. In a read/write application, the base station is not only capable of sending an excitation signal and receiving a response from the radio frequency identification tag, but it is also capable of sending a data, or write, signal to the radio frequency identification tag. The radio frequency identification tag receives the write signal, which may contain data to be stored within the tag, a code or a command. Depending on the type of write signal, the radio frequency identification tag responds accordingly, such as by storing the data or acting upon the command.
In the past, the read range of the radio frequency identification tag was relatively small. Thus, in order to read the information from the tag, an exciter/reader would have to be brought very close to the article which tag was being read, and/or the article brought very close to the exciter/reader. Neither of these conditions are possible when the articles are being automatically transported along conveyors and similar material handling devices. Thus, radio frequency identification tag technology has not, to date, found widespread use in manufacturing, article conveyance, inventory management, parcel delivery tracking and similar applications.
Advances in radio frequency identification tag technology set forth in the above-referenced and incorporated United States patent applications greatly increase the read ranges of radio frequency identification tags. With improved read ranges, radio frequency identification tags become a desirable technology for article tracking in manufacturing, inventory and sales applications as well as in mail and parcel delivery services. The improvements provide increased read ranges and reduced sensitivity to orientation. And, unlike optical technologies, such as bar codes, do not require line of sight access. However, exciter/reader devices are not available for these applications.
Thus there is a need for a radio frequency identification tag exciter/reader.